PHOTO: Jake Gyllenhaal's Amazing Abs in Prince of Persia

In newly released images from his summer action movie Prince of Persia: The Sands of Time, which opens May 28, Jake Gyllenhaal shows off a seriously buff bod.

Gyllenhaal, 29, worked hard to bulk up for the role, for which he also trained in parkour (the sport of running, jumping and climbing over obstacles).

“It’s a physical role,” he told fans at the Wondercon convention in San Francisco earlier this month. “I never did anything this intensive before [to transform my body]. When you are committed, you are committed.”

But hey, why not? Said Gyllenhall: “It was so much fun to get paid to get tanned and get in shape.”

Meet Sandra Bullock’s baby! For the whole story – including photos of her son Louis, an emotional interview about her breakup with Jesse James and her life as a new mom – pick up the new issue of PEOPLE, on newsstands Friday